Such a process is known from e.g. WO 2013/048248. In this application it is described that there is an increasing tendency to create chemicals from renewable sources. Research has been undertaken to prepare chemicals from biomass materials, such as carbohydrates, e.g. cellulose, starch, hemicelluloses, sugars, glucose and fructose. Dehydration of such carbohydrates may yield valuable chemicals, including levulinic acid, furfural, hydroxymethyl furfural and derivatives thereof. In WO 2013/048248 the reaction is disclosed wherein a 2-alkoxymethyl furan is reacted with a substituted olefin to yield an unsaturated bicyclic ether. The bicyclic ether is subsequently dehydrated and aromatized to yield a substituted benzene compound. Via this process substituents on the 1,2-, 1,3- or 1,2,3-positions of the benzene ring are obtained. The thus obtained products may elegantly be converted by oxidation into phthalic acid, isophthalic acid and hemimellitic acid.
In US 2010/0127220 a process for the manufacture of substituted pentacenes is described. The process includes a step wherein dimethylfuran is reacted with maleic anhydride via a Diels Alder reaction to yield a bicyclic unsaturated ether. The bicyclic unsaturated ether is then dehydrated and aromatized under aromatization conditions to yield 4,7-dimethyl-isobenzofuran-1,3-dione (see reaction scheme A, wherein step (i) is a Diels-Alder reaction and step (ii) is the aromatization).

It appears that the yield of the bicyclic unsaturated ether can be relatively high. An example in WO 2013/048248 shows that the yield of the bicyclic unsaturated ether can be about 96%. According to an example in US 2010/0127220 a yield of about 72% could be obtained in the preparation of the bicyclic unsaturated ether (cf. US 2010/0127220, Example 1). However, both documents also show that the yield of the subsequent dehydration is significantly lower. According to Example 2 in WO 2013/048248 the desired benzene compound could be obtained in a yield of 37%, whereas the yield on the desired benzene compound in US 2010/0127220 amounted to about 41%. When the yields are calculated on the basis of the starting furan compound the overall yield is about 30 to 35% according to the examples in these documents.
It has now been found that the overall yield of the preparation process can be increased when the dehydration step of the bicyclic unsaturated ether is preceded by a hydrogenation step, wherein the unsaturated bond of the bicyclic unsaturated ether that is obtained in the reaction of the furan compound with the olefin is hydrogenated. Surprisingly, the saturated bicyclic ether thus obtained can still be dehydrated and aromatized, yielding the desired benzene compound.